Resorbable anchor arrangements for implantable devices and methods of making and using

ABSTRACT

An implantable device includes a device body and at least one anchoring unit configured and arranged for anchoring the device body in a patient upon implantation. The anchoring unit includes a resorbable material that resorbs into the patient over a period of time after implantation.

FIELD

The invention is directed to implantable devices that include resorbableanchor arrangements, and methods of making and using the devices. Inaddition, the invention is directed to implantable leads having one ormore resorbable anchor arrangements and methods of making and using theleads.

BACKGROUND

Implantable electrical stimulation devices have proven therapeutic in avariety of diseases and disorders. For example, pacemakers andimplantable cardiac defibrillators have proven effective in thetreatment of cardiac conditions. Spinal cord stimulation systems havebeen used as a therapeutic modality for the treatment of chronic painsyndromes. Deep brain stimulation has also been useful for treatingrefractory chronic pain syndromes and has been applied to treat movementdisorders and epilepsy. Peripheral nerve stimulation has been used totreat chronic pain syndrome and incontinence, with a number of otherapplications under investigation. Functional electrical stimulationsystems have been applied to restore some functionality to paralyzedextremities in spinal cord injury patients.

Implantable drug delivery systems allow highly concentrated drugs to bedelivered to specific sites. This site specific delivery can result inreduced side effects, improved quality of life, and, in some cases, mayextend life. Such drug delivery systems include both programmable pumpsand constant flow pumps. Examples of such systems include intrathecaldrug delivery for the treatment of chronic intractable pain; delivery ofbaclofen for the treatment of spasticity; site specific delivery ofdrugs for the treatment of cancer, and site specific insulin deliveryfor the management of diabetes.

One disadvantage of these devices is that the electrode lead or drugcatheter may migrate within the body. Migration may result in failure ofthe therapy or unwanted side effects. A variety of methods have beenused to fix the lead or catheter including sutures and cuffs. While suchfixation can be useful to prevent or reduce lead or catheter migration,many leads and catheters are eventually removed due to, for example,patient request, therapy completion or failure, infection, etc. Thesefixation methods can make removal of the implantable device moredifficult.

BRIEF SUMMARY

One embodiment is an implantable device that includes a device body andat least one anchoring unit configured and arranged for anchoring thedevice body in a patient upon implantation. The anchoring unit includesa resorbable material that resorbs into the patient over a period oftime after implantation.

Another embodiment is a method of implanting a device. The methodincludes implanting an implantable device body and coupling an anchoringunit to tissue. The anchoring unit allows fixation of the device body tothe tissue. The anchoring unit includes resorbable material.

Yet another embodiment is an implantable device that includes a controlunit, an implantable device body combined with the control unit andconfigured and arranged to be implanted proximate to selected tissue ina patient, and at least one anchoring unit configured and arranged foranchoring the implantable device body in the patient upon implantation.The anchoring unit includes a resorbable material that resorbs into thepatient over a period of time after implantation.

BRIEF DESCRIPTION OF THE DRAWINGS

Non-limiting and non-exhaustive embodiments of the present invention aredescribed with reference to the following drawings. In the drawings,like reference numerals refer to like parts throughout the variousfigures unless otherwise specified.

For a better understanding of the present invention, reference will bemade to the following Detailed Description, which is to be read inassociation with the accompanying drawings, wherein:

FIG. 1 is a schematic perspective view of one embodiment of animplantable device with a resorbable anchor arrangement, according tothe invention;

FIG. 2 is a schematic perspective view of another embodiment of animplantable device with a resorbable anchor arrangement, according tothe invention;

FIG. 3 is a schematic perspective view of a third embodiment of animplantable device with a resorbable anchor arrangement, according tothe invention;

FIG. 4 is a schematic perspective view of a fourth embodiment of animplantable device with a resorbable anchor arrangement, according tothe invention;

FIG. 5 is a schematic perspective view of the implantable device of FIG.4 disposed over a nerve;

FIG. 6 is a schematic perspective view of the implantable device of FIG.4 with the resorbable anchor arrangement removed;

FIG. 7 is a schematic perspective view of the implantable device of FIG.4 disposed over a nerve and with the resorbable anchor arrangementremoved;

FIG. 8 is a schematic perspective view of a fifth embodiment of animplantable device with a resorbable anchor arrangement wrappedhelically around a nerve, according to the invention; and

FIG. 9 is a schematic perspective view of the implantable device of FIG.8 with the resorbable anchor arrangement removed.

DETAILED DESCRIPTION

The invention is directed to implantable devices that include resorbableanchor arrangements, and methods of making and using the devices. Inaddition, the invention is directed to implantable leads having one ormore resorbable anchor arrangements and methods of making and using theleads.

Suitable implantable devices include, but are not limited to, electrodeleads, catheters, sensors, and transmitters. For example, theimplantable device can be an electrode lead with one or more electrodesdisposed on a distal end of the lead and one or more terminals disposedon a proximal end of the lead. One embodiment of a resorbable anchorarrangement includes the electrodes disposed on the resorbable material.In another embodiment, the resorbable anchor arrangement can be disposedaround or attached to the electrode lead. Electrodes leads include, forexample, percutaneous leads and paddle leads. Examples of stimulatorsystems with electrode leads are found in U.S. Pat. Nos. 6,181,969;6,516,227; 6,609,029; 6,609,032; and 6,741,892; and U.S. PatentApplication Serial No. 11/238,240, all of which are incorporated byreference.

A resorbable anchor arrangement can also be used to fix amicrostimulator in place. Examples of suitable microstimulators aredescribed in U.S. Pat. Nos. 5,193,539; 5,193,540; 5,312,439; 6,051,017;and 6,609,032; U.S. Patent Application Publication No. 2004/059392; U.S.Patent Applications Serial Nos. 11/040,209 and 11/056,762; and PCTPatent Applications Publication Nos. 98/37926; 98/43700; and 98/43701,all of which are incorporated herein by reference. The BION™microstimulator, available from Advanced Bionics Corporation, Sylmar,CA, is an example of a microstimulator.

A resorbable anchor arrangement can also be used to fix a catheter inplace. For example, the catheter can be a portion of an implantable drugdelivery system. The catheter is typically implanted in the proximity ofthe tissue to be treated.

Implantable sensors can also be fixed using a resorbable anchorarrangement. Examples of sensors include, but are not limited to,electrical activity sensors (e.g., electroencephalograph,electrocardiograph, electromygraph, and electronystagmograph sensors);chemical sensors (e.g., glucose and drug sensors); and mechanicalactivity sensors (e.g., pressure, strain, stress, position, velocity,and acceleration sensors.)

These types of implantable devices can also be combined. For example, anelectrode lead may also include a catheter lumen to provide drugs orother medications to the tissue to be stimulated or to other proximatetissue. As another example, an electrode lead can include one or more ofthe sensors described above. Yet another example is a catheter thatincludes one or more of the above-described sensors.

The resorbable anchor arrangement allows the implantable device to befixed to the tissue at the implantation site using, for example,sutures, staples, and adhesive, or by at least partially wrapping theresorbable anchor arrangement around the tissue, for example, as a cuffor as a ribbon wrapped around a portion of a nerve, vein, artery,muscle, ligament, or organ. The resorbable material of the anchorarrangement is resorbed by the body of the patient over time. Theresorbtion typically releases, at least partially, the implantabledevice from the anchor arrangement. This release can assist in the laterremoval of the implantable device. In some instances, the implantabledevice may even be withdrawn from the implantation site by pulling onthe device (e.g., on an electrode lead or catheter.)

The resorbtion time for the resorbable material can be selected, ifdesired, to provide an average lifetime for the anchoring arrangement.For example, the resorbtion material may have an average resorbtion timeof 1 week, 1 month, 6 months, 1 year, 2 years, 5 years, 10 years, orlonger. The selection of a resorbtion time can be based on one or morefactors such as, for example, the implantable device, the site ofimplantation, the expected lifetime of the implantable device, theexpected duration of implantation, the age of the patient, expectedgrowth rate of tissue around the implanted device, and the expectedmaturation rate of the capsule surrounding device. It will be recognizedthat there may be substantial variation from the average resorbtion timein actual devices. The actual resorbtion time may depend on theconditions within the patient's body.

Examples of suitable resorbable material include, but are not limitedto, polylactide (PLA), polyglycolide (PGA), poly(lactide-co-glycolide)(PLGA), poly(e-caprolactone), polydioxanone, polyanhydride, trimethylenecarbonate, poly((β -hydroxybutyrate), poly(g-ethyl glutamate), poly(DTHiminocarbonate), poly(bisphenol A iminocarbonate), poly(ortho ester)s(POEs), polycyanoacrylate, polyphosphazene, modified polysaccharides(for example, cellulose, chitin, dextran), and modified proteins (forexample, fibrin, casein).

In some embodiments, the resorbable anchor arrangement may also have adrug, medication, tissue growth enhancer, or other agent disposed in theresorbable material for time release. For example, the resorbablematerial may be combined with a drug or other medication to treat thetissue at the implantation site or to reduce pain or inflammation. Asanother example, the resorbable material may be combined with asubstance that promotes tissue growth and encapsulation of at least aportion of the implantable device. Generally, the drug, medication, orother agent is released over time as the resorbable material is resorbedby the patient's body.

In at least some embodiments, the anchoring arrangement is configured toenhance tissue fixation of the implantation device, to replace theanchoring arrangement, as the material is resorbed into the body of thepatient. As indicated above, the anchoring arrangement may include asubstance that promotes tissue growth or encapsulation. Additionally oralternatively, the shape of the anchoring arrangement may promoteencapsulation; the anchoring arrangement may include grooves or poresthat promote tissue in-growth to stabilize the implantable device inplace; or the shape may have a three-dimensional structure that providesa scaffold to enhance and guide the direction of tissue growth. In atleast some instances, the implantable device may be later removed orexplanted by pulling on the device. The device preferably follows a pathalong the encapsulating tissue. This procedure, preferably, reducestissue damage that would occur if the implantable device were otherwiseremoved.

FIGS. 1-3 illustrate embodiments of one type of anchoring arrangement.This type of anchoring arrangement 102 a, 102 b, 102 c fits around aportion of an implantable device, such as an electrode lead 104 (or acatheter, sensor, or transmitter.) The anchoring arrangement is at leastpartially, and preferably fully, formed of resorbable material. Theanchoring arrangement can be formed integrally with the implantabledevice or the anchoring arrangement can be a separate component that canbe slid onto or otherwise attached to the implantable device. In oneembodiment, the anchoring arrangement is made to fit onto an existingimplantable device. This can allow a practitioner or other to retrofitexisting implantable devices. These anchoring arrangements 102 a, 102 b,102 c can be sutured, stapled, glued, or otherwise attached to thetissue of the patient to fix the implantable device in place duringimplantation.

The anchoring arrangement 102 a of FIG. 1 fits around the electrode lead104 so that a suture 106 or other fastener (e.g., a staple) can passbetween the body of the anchoring arrangement and the lead to allowfixation of the lead to the surrounding tissue. In the illustratedexample, the anchoring arrangement 102 a is a ring of material, however,it will be recognized that other shapes can also be used. As theanchoring arrangement is resorbed into the body of the patient, thesuture is released. The suture 106 is optionally formed of resorbablematerial.

The anchoring arrangement 102 b of FIG. 2 includes one or more openings108 through which a suture 106 or other fastener (e.g., a staple) canpass to allow fixation of the lead to the surrounding tissue. Althoughthe anchoring arrangement 102 b is illustrated as a separate componentthat can be slid onto the lead 104, it will be recognized that theanchoring arrangement can also be integrally formed with the lead. Asthe anchoring arrangement is resorbed into the body of the patient, thesuture is released.

The anchoring arrangement 102 c of FIG. 3 includes a mass of resorbablematerial disposed on the lead 104. In at least some instances, thisanchoring arrangement can be anchored in position simply by thesurrounding tissue. Optionally, the shape of the anchoring arrangementcan be selected to prevent or resist rotations of the electrode leadand/or lateral or longitudinal movement of the lead when implanted inthe body. In some instances, a fastener, such as a suture or staple, canpenetrate the resorbable material of the anchoring arrangement 102 c toprovide further fixation for the lead 104. An another alternative, theanchoring arrangement 102 c can be adhesively attached to surroundingtissue. Any fastener or adhesive attachment is released upon resorbtionof the material of the anchoring arrangement.

FIGS. 4-7 illustrate another embodiment of an anchoring arrangement 202.The anchoring arrangement 202 is provided as a cuff upon which one ormore electrodes 206 (or sensors or catheter lumens) are disposed. Theelectrodes can be, for example, metal wires that are disposed on orwithin the material of the cuff. The electrodes 206 are (individually,collectively, or otherwise) coupled to a lead 204 that is connected to apulse generator (not shown) which provides electrical pulses along oneor more conductors 208 to the electrodes. As illustrated in FIG. 5, thecuff of the anchoring arrangement 202 can be positioned around a portion210 of the body, such as a nerve, artery, vein, tissue, or organ. Theanchoring arrangement 202 holds the electrodes 206 in place.

Preferably, the electrodes and conductors are made of a flexibleelectrically conducting material and can be a single strand or multiplestrands. Examples of suitable materials for the electrodes andconductors include stainless steel, platinum, iridium, titanium, and thelike. The electrodes and conductors can be uninsulated or insulated.Typically, those regions of the electrodes through which current is tobe provided directly to the tissue are uninsulated.

The cuff of the anchoring arrangement 202 is formed, at least in part,of resorbable material which is resorbed into the body of the patientover time leaving the electrodes 206, as illustrated in FIGS. 6 and 7.As described above, tissue may be encouraged to grow around theelectrodes or lead to stabilize the structure over time.

This embodiment can be modified by including one or more sensors ortransmitters, in addition to or as an alternative to the electrodes. Theembodiment can also be altered modified to include a catheter lumen thatextends through the lead to the cuff. The cuff supports the end portionof the catheter lumen with one or more openings in the catheter lumenfor providing the drug, medication, or other agent.

Another embodiment of an implantable device with an anchoringarrangement 302 is illustrated in FIGS. 8 and 9. The anchoringarrangement 302 is configured to be wrapped around a portion 310 of thebody of the patient, such as a nerve, vein, artery, organ, or othertissue, as illustrated in FIG. 8. The anchoring arrangement 302 can bewrapped in any way including in a helical manner. The electrodes 306 canbe carried on or in the material of the anchoring arrangement 302. Theelectrodes 306 are coupled to a lead 304 and conductors 308. Over time,the material of the anchoring arrangement is resorbed, as illustrated inFIG. 9, to leave the electrodes 306. This embodiment can be modified, asdescribed above, for use with a catheter, sensor, and/or transmitter.

The electrode leads, catheters, sensors, and transmitters describedherein are typically coupled to an implantable or external control unitas part of an implantable system or device. For example, an electrodelead can be coupled to an implantable pulse generator and a catheter canbe coupled to an implantable or external drug delivery pump.

The above specification, examples and data provide a description of themanufacture and use of the composition of the invention. Since manyembodiments of the invention can be made without departing from thespirit and scope of the invention, the invention also resides in theclaims hereinafter appended.

1. An implantable device, comprising: a device body configured andarranged to be implanted proximate to selected tissue in a patient, thedevice body comprising a distal portion, a proximal portion, at leastone electrode disposed on the distal portion of the device body, atleast one terminal disposed on the proximal portion of the device body,and at least one conductor extending along the device body from the atleast one electrode to the at least one terminal, wherein the at leastone terminal is configured and arranged to mechanically couple to anexternal pulse generator; and an anchoring unit disposed around aportion of the device body between the at least one electrode and the atleast one terminal, the anchoring unit configured and arranged foranchoring the device body in the patient upon implantation, theanchoring unit comprising a ring-shaped unit forming, by itself, aclosed loop, the ring-shaped unit formed from a resorbable material thatresorbs into the patient over a period of time after implantation, theresorption at least partially releasing the at least one electrode fromthe anchoring unit while the device body is implanted in the patient,the anchoring unit configured and arranged such that the period of timeof resorption is sufficient to allow tissue ingrowth around the at leastone electrode to anchor the at least one electrode prior to release ofthe at least one electrode due to at least a partial resorption of theanchoring unit.
 2. The implantable device of claim 1, wherein the atleast one anchoring unit is configured and arranged for suturing thedevice body to tissue using the at least one anchoring unit, whereinresorption of the at least one anchoring unit into the patient releasesthe device body from the sutures.
 3. The implantable device of claim 1,wherein the at least one anchoring unit and device body are configuredand arranged such that a suture can pass between the at least oneanchoring unit and the device body.
 4. The implantable device of claim1, wherein the at least one anchoring unit defines at least one openingtherethrough for passage of a suture.
 5. The implantable device of claim1, wherein the at least one anchoring unit is configured and arrangedfor stapling the device body to tissue using the at least one anchoringunit, wherein resorption of the at least one anchoring unit into thepatient releases the device body from the staples.
 6. The implantabledevice of claim 1, wherein the at least one anchoring unit is configuredand arranged for gluing the device body to tissue using the at least oneanchoring unit, wherein resorption of the at least one anchoring unitinto the patient releases the device body from the glue.
 7. Theimplantable device of claim 1, wherein the anchoring unit is formedintegrally with the device body.
 8. The implantable device of claim 1,wherein the anchoring unit is removable from the device body.
 9. Theimplantable device of claim 1, wherein the at least one anchoring unitcouples to the implantable device body by sliding the at least oneanchoring unit over at least a portion of the implantable device body.10. The implantable device of claim. 1, wherein the device body isconfigured and arranged for explantation from the patient after theresorbable material is resorbed by the patient.
 11. The implantabledevice of claim 1, wherein the anchoring unit is disposed completelyaround the device body such that the entire anchoring unit is positionedbetween the at least one electrode and the at least one terminal.
 12. Astimulation system comprising: the implantable device of claim 1, and acontrol unit configured and arranged for receiving the proximal portionof the device body of the implantable device.
 13. The stimulation systemof claim 12, wherein the control unit is also implantable.
 14. Thestimulation system of claim 12, wherein the control unit comprises animplantable pulse generator coupled to the proximal portion of thedevice body, wherein the implantable pulse generator provides electricalpulses along the at least one conductor of the implantable device to theat least one electrode of the implantable device.
 15. The stimulationsystem of claim 14, wherein the implantable pulse generator isconfigured and arranged for implantation at a location that is remotefrom the at least one anchoring unit.
 16. A method of implanting thestimulation system of claim 1, the method comprising: implanting thedevice body of the stimulation system into a patient; disposing the atleast one anchoring unit of the stimulation system around a portion ofthe device body between the at least one electrode and the at least oneterminal of the device body; and anchoring the at least one anchoringunit to the patient upon implantation such that the device body isdisposed proximate to selected patient tissue.
 17. The method of claim16, further comprising applying tissue growth enhancer to the at leastone anchoring unit.
 18. The method of claim 16, further comprisingremoving the device body after enough of the resorbable material isresorbed by the patient to at least partially release the at least oneelectrode from the anchoring unit.
 19. The method of claim 18, whereinresorption of the anchoring unit fully releases the at least one of theelectrodes from the at least one anchoring unit.
 20. The method of claim1, wherein anchoring the at least one anchoring unit to the patientcomprises suturing the device body to patient tissue using the at leastone anchoring unit.